The present invention relates to a bi-directional cutting or trimming knife and method for using same.
Trimming knives have been used to trim the edges of a stack of sheet members. An example of such a use is the trimming in a bindery of the edges of bound books. Trimming knives for accomplishing this function generally move in a downward direction and in a lateral direction with respect to the sheet members being trimmed. However, prior art trimming knives generally are capable of moving only in a single lateral direction during the trimming process.
Cutting knives have been used to cut the edges of a stack of unbound sheet members. Cutting knives, like trimming knives, have generally been capable of moving only in a single lateral direction.
Therefore a primary object of the present invention is the provision of a bi-directional cutting or trimming knife and method for using same.
A further object of the present invention is the provision of a cutting or trimming knife which can be moved in a first lateral direction or in a second lateral direction during the downward movement of the knife towards the sheet members being trimmed.
A further object of the present invention is the provision of a cutting or trimming knife which is bi-directional, but which is rigidly held in proper alignment during its trimming action.
A further object of the present invention is the provision of a cutting or trimming knife which can be easily and rapidly transferred from a first position to be movable in one lateral direction during one trimming or cutting cut, to a second position movable in another lateral direction during another trimming or cutting cut.
A further object of the present invention is the provision of a cutting or trimming knife which can be easily and rapidly transferred from a first position to be movable in one lateral direction during one trimming or cutting motion, to a second position movable in another lateral direction during another trimming or cutting motion.
A further object of the present invention is the provision of a cutting or trimming knife that will not dull as quickly due to full use of the length of the knife edge.
A further object of the present invention is the provision of a bi-directional cutting or trimming knife which is economical to manufacture, durable in use, and efficient in operation.
The foregoing objects may be achieved by an apparatus for trimming or cutting a stack of sheet members having edges to be trimmed and being supported on a cutting table. The apparatus includes an elongated knife having a cutting edge extending along the cutting axis of the knife. A knife supporting frame is connected to the cutting table and a guide mechanism mounts the knife to the supporting frame for movement of the knife from a start position wherein the knife is positioned spaced from the cutting table and the sheet members to a cut position wherein the knife moves towards the cutting table and cuts or trims the stack of sheet members. At least a portion of the guide mechanism is movable on the frame to a first guide position causing the knife to move in a first direction relative to the cutting edge axis when moving from its starting position to its cut position. At least a portion of the guide mechanism is movable on the frame to a second guide position causing the knife to move in a second direction opposite from the first direction when moving from its start position to its cut position.
The guide mechanism may include a linkage which pivots during movement of the knife between its start and cut positions. However other guide mechanisms can also be used such as slots in plates for guiding the knife. Other mechanisms also may be used for guiding the knife bi-directionally.
The method for using the knife includes cutting or trimming the first edge of the stack of sheet members by moving the cutting edge of the knife in a downwardly inclined direction extending both toward the first edge of the stack and in a first lateral direction along the knife axis until the cutting edge engages and trims the first edge of the stack of sheet members. The knife is then lifted upwardly away from the stack of sheet members. A second trimming step includes trimming the second edge of the stack by moving the cutting edge of the knife in a downwardly inclined direction extending both toward the second edge of the stack and in a second lateral direction opposite from the first lateral direction until the cutting edge engages and trims the second edge of the stack of sheet members.